TECHNICAL FIELD
[0001] The present invention relates to a communication device operating as a terminal in
a communication system having a base station accommodating the terminal, and a communication
method as well as a communication system, and particularly to a communication device
for reducing consumed power due to intermittent reception while receiving paging information
or other necessary information from a base station, and a communication method as
well as a communication system.
BACKGROUND ART
[0002] A variety of communication services have been spread due to widely-used information
processing and information communication techniques, and particularly communication
systems including cell phones have been remarkably developed. At present, for 3GPP
(Third Generation Partnership Project), the global standard of the third generation
(3G) mobile communication system "IMT (International Mobile Telecommunications)-2000"
defined by ITU (International Telecommunication Union) is being standardized. One
data communication specification "LTE (Long Term Evolution)" defined by 3GPP is a
long-term advanced system directed for the fourth generation (4G) IMT-Advanced, and
is called "3.9G (super 3G)."
[0003] For example, a communication system having a base station accommodating a terminal
has a problem of how to reduce consumed power of the terminal. In particular, it is
important to reduce consumed power when the terminal is not making communication.
Intermittent reception is widely known as one method for solving the problem. Intermittent
reception is a communication control system for keeping a period for receiving a signal
from a communication network at minimum while the terminal is not making communication,
and for powering off a receiver during the remaining period thereby to reduce consumed
power. For example, a cell phone powers on the receiver for receiving essential information
such as paging information for a communication operation from a base station and powers
off the receiver during other period. For the above 3GPP, an outline of the intermittent
reception as DRX (discontinuous reception) is described (see Non-Patent Document 1,
for example).
[0004] There are proposed a method for dividing terminals into a plurality of groups, shifting
a cycle of DRX per group, and reducing a rate of the ON state in each cycle of DRX
thereby reducing consumed power (see Patent Document 1, for example), and a method
for using DRX with different cycles depending on a time (for example, daytime and
nighttime), thereby further elongating the cycle of DRX (see Patent Document 2, for
example).
[0005] A communication network is widely used in other than terminals directly used by persons
for communication such as meters, automatic venders and electronic advertisements
in addition to normal terminals directly used by persons such as conventional cell
phones and PC (personal computer). In the following, the communication which is not
directly used by persons is called MTC (Machine Type Communication), and a terminal
which is not directly used by a person for communication is called a MTC terminal.
[0006] For MTC, a communication frequency necessary for the MTC terminal is relatively lower
than the normal terminals (such as once a day, once a week or once a month), and the
amount of data used for communication at a time is not large. On the other hand, it
is expected that remarkably small consumed power is needed for the MTC terminal.
[0007] When the cycle of DRX is simply made longer for reducing consumed power, the terminal
can fail to receive system information or paging information transmitted from the
communication network. Thus, the terminal intermittently operates while securing a
chance to accurately receive information from the communication network (the base
station), thereby to further reduce consumed power of the terminal.
[0008] It is assumed that the communication of the MTC terminal is made according to a communication
schedule desired by users inside the communication network or users outside the communication
network. In this case, the communication network (the base station) needs to grasp
the communication schedule and reflect it on the DRX setting in order to meet the
conditions of the user-desired communication schedule.
CITATION LIST
PATENT DOCUMENTS
[0009]
Patent Document 1: Japanese Patent No. 2669891
Patent Document 2: Japanese Patent No. 3270306
NON-PATENT DOCUMENT
SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0011] It is an object of the present invention to provide a communication device excellent
and capable of intermittently operating as a terminal suitably in a communication
system having a base station accommodating the terminal, and a communication method
as well as communication system.
[0012] It is another object of the present invention to provide a communication device excellent
and capable of intermittently operating as a terminal suitably while receiving paging
information or other necessary information from a base station, and a communication
method as well as a communication system.
[0013] It is still another object of the present invention to provide a communication device
excellent and capable of suitably making communication as a terminal while intermittently
operating according to a communication schedule desired by users inside and outside
a communication network, and a communication method as well as a communication system.
SOLUTIONS TO PROBLEMS
[0014] The present application has been made in view of the above problems, and an invention
according to claim 1 is a communication device including: a communication processing
unit for performing digital processing and analog processing for transmitting and
receiving data; and an intermittent operation control unit for determining whether
to enter an intermittent operation period for intermittently operating the communication
processing unit per second cycle by use of information on a first cycle longer than
the second cycle, and for intermittently operating the communication processing unit.
[0015] With an invention according to claim 2 of the present application, the communication
device according to claim 1 has a normal operation mode in which a communication operation
is always performed in the communication processing unit and an intermittent operation
mode in which a communication operation of the communication processing unit is intermittently
performed. The intermittent operation control unit determines, based on the first
cycle, whether to enter the intermittent operation period in the intermittent operation
mode.
[0016] With an invention according to claim 3 of the present application, in the communication
device according to claim 1 or 2, the intermittent operation control unit turns off
at least part of circuits in the communication processing unit in a period other than
the intermittent operation period.
[0017] With an invention according to claim 4 of the present application, the intermittent
operation control unit of the communication device according to claim 1 generates
a first timing signal which is switched on or off by the first cycle and a second
timing signal which is switched on or off by the second cycle based on control information
on the first and second cycles from a predetermined base station when being accommodated
in a communication network of the base station, and determines the intermittent operation
period based on the first timing signal and intermittently operates the communication
processing unit based on the second timing signal in the intermittent operation period.
[0018] With an invention according to claim 5 of the present application, in the communication
device according to claim 4, the ON period of the first timing signal is longer than
the ON period of the second timing signal.
[0019] With an invention according to claim 6 of the present application, the intermittent
operation control unit of the communication device according to claim 4 assumes the
ON period of the first timing signal as the intermittent operation period, turns off
at least part of the circuits in the communication processing unit in the OFF period
of the first timing signal, turns on a communication operation of the communication
processing unit in the ON period of the second timing signal in the intermittent operation
period, and turns off the communication processing unit in the OFF period of the second
timing signal.
[0020] With an invention according to claim 7 of the present application, the intermittent
operation control unit of the communication device according to claim 4 starts the
intermittent operation period when the first timing signal is turned on in other than
the intermittent operation period, terminates the intermittent operation period when
the first timing signal is turned on in the intermittent operation period, turns on
a communication operation of the communication processing unit in the ON period of
the second timing signal in the intermittent operation period, and turns off at least
part of the circuits in the communication processing unit in the OFF period of the
second timing signal.
[0021] With an invention according to claim 8 of the present application, the intermittent
operation control unit of the communication device according to claim 4 assumes the
ON period of the first timing signal as the intermittent operation period, turns off
at least part of the circuits in the communication processing unit in the OFF period
of the first timing signal, turns on a communication operation of the communication
processing unit when the second timing signal is turned on in the OFF state of the
communication processing unit in the intermittent operation period, and turns off
the communication processing unit when the second timing signal is turned on in the
ON state of the communication operation of the communication processing unit.
[0022] With an invention according to claim 9 of the present application, the intermittent
operation control unit of the communication device according to claim 4 turns off
at least part of the circuits in the communication processing unit when all necessary
reception processing from the communication network ends even in a period which is
determined to turn on the communication processing unit based on the second timing
signal in the intermittent operation period.
[0023] With an invention according to claim 10 of the present application, predetermined
correction processing is performed on a receiver in the communication processing unit
when at least part of the circuits in the communication processing unit of the communication
device according to claim 1 enters the intermittent operation period from the OFF
state and receives radio frames again.
[0024] With an invention according to claim 11 of the present application, in the communication
device according to claim 10, predetermined correction processing is performed on
a receiver in the communication processing unit in the intermittent operation period
and when the communication processing unit is in the OFF state.
[0025] With an invention according to claim 12 of the present application, the communication
device according to claim 1 is configured such that the first intermittent operation
mode has a first-2 cycle shorter than the first cycle, and when a predetermined even
occurs, the intermittent operation mode switch unit replaces the first cycle with
the first-2 cycle and determines a period of entering the second intermittent operation
mode.
[0026] An invention according to claim 13 of the present application is a communication
method including: a first step of determining whether to enter an intermittent operation
period for intermittently operating a communication device based on information on
a first cycle; and a second step of switching an ON state of a communication operation
of the communication device and an OFF state of at least part of circuits per second
cycle shorter than the first cycle in the intermittent operation period.
[0027] With an invention according to claim 14 of the present application, in the invention
according to claim 13, the communication device has a normal operation mode of always
performing a communication operation and an intermittent operation mode of intermittently
performing a communication operation. The first step of the communication method according
to claim 13 determines whether to enter the intermittent operation period in the intermittent
operation mode based on the information on the first cycle, and further has a step
of turning off the communication device in other than the intermittent operation period
in the intermittent operation mode.
[0028] An invention according to claim 15 of the present application is a communication
method including a first step of notifying parameters of the first intermittent operation
mode for intermittent operation per first cycle and parameters of the second intermittent
mode for intermittent operation per second cycle shorter than the first cycle, and
a second step of notifying control information on the network to a communication device
in the network in association with the first intermittent operation mode or the second
intermittent operation mode.
[0029] An invention according to claim 16 of the present application is configured such
that the second step in the communication method according to claim 15 is directed
for notifying the control information on the network to the communication device in
the network in association with a period in which the communication device in the
network performs a communication operation in the first intermittent operation mode
or in the second intermittent operation mode.
[0030] An invention according to claim 17 of the present application is a communication
system including a base station for operating a communication network, and a terminal
which includes a communication processing unit for performing digital processing and
analog processing for transmitting and receiving data to and from the base station,
sets a first cycle of a first intermittent operation mode and a second cycle of a
second intermittent operation mode based on control information notified from the
communication network, determines a period of entering the second intermittent operation
mode based on the first cycle, turns off at least part of circuits in the communication
processing unit in other than the period of entering the second intermittent operation
mode in the first intermittent operation mode, and performs an intermittent operation
on the communication processing unit per second cycle in the second intermittent operation
mode.
[0031] The "system" described herein refers to a logical collection of devices (or function
modules for realizing specific functions), and each device or function module may
be or may not be in a single casing.
[0032] According to the present invention, there can be provided, in the communication system
having a base station accommodating a terminal, a communication device excellent and
capable of intermittently operating as a terminal suitably while receiving paging
information or other necessary information from the base station, and a communication
method as well as a communication system.
[0033] According to the present invention, there can be provided a communication device
excellent and capable of suitably making communication as a terminal while intermittently
operating according to a communication schedule desired by users inside and outside
the communication network, and a communication method as well as a communication system.
[0034] With the invention according to claims 1 to 9 and 13 to 17 of the present application,
the communication device uses the cycles of DRX with different lengths in a hierarchy
manner thereby to acquire necessary information from the communication network in
short cycle DRX while achieving a reduction in consumed power at the terminal in long
cycle DRX (long sleep state).
[0035] With the invention according to claims 10 and 11 of the present application, since
the correction processing such as synchronization or pull-in is performed on the communication
processing unit when the communication processing unit transits to the ON state and
receives radio frames again, the reception operation can be correctly performed even
in the OFF (sleep) state for a long time.
[0036] With the invention according to claim 12 of the present application, two cycles with
different lengths in the same DRX mode are defined and the long cycle is typically
used, but when an event occurs, the cycle is switched to the short cycle, and thus
the terminal can rapidly connect to the communication network when an event occurs.
Thereby, the communication schedule of the terminal can be notified to the communication
network via the server from the users inside and outside the communication network,
and the schedule can be reflected on generation of the DRX cycle.
[0037] Other additional objects, characteristics and advantages of the present invention
will be apparent with more detailed description based on the embodiment of the present
invention and the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0038]
Fig. 1 is a diagram schematically illustrating a structure of a communication network
to which the present invention is applied.
Fig. 2 is a diagram schematically illustrating other structure of the communication
network to which the present invention is applied.
Fig. 3 is a diagram illustrating an exemplary structure of a radio frame transmitted
from a base station to a terminal, which is defined by LTE of 3GPP.
Fig. 4 is a diagram schematically illustrating how resource blocks are allocated.
Fig. 5 is a diagram schematically illustrating an exemplary structure of a communication
device operating as a terminal in a communication network of a base station.
Fig. 6 is a diagram illustrating an exemplary internal structure of a DRX control
unit 56.
Fig. 7 is a diagram illustrating exemplary DRX in which DRX1 having a long cycle T_DRX1
and DRX2 having a short cycle T_DRX2 are used in a hierarchy manner.
Fig. 8 is a diagram illustrating another exemplary DRX in which DRX1 having a long
cycle T_DRX1 and DRX2 having a short cycle T_DRX2 are used in a hierarchy manner.
Fig. 9 is a diagram illustrating still another exemplary DRX in which DRX1 having
a long cycle T_DRX1 and DRX2 having a short cycle T_DRX2 are used in a hierarchy manner.
Fig. 10 is a flowchart illustrating a processing procedure performed by a communication
device 50 operating as a terminal in a communication network in an intermittent operation
(DRX) mode.
Fig. 11 is a flowchart illustrating another exemplary processing procedure performed
by the communication device 50 operating as a terminal in a communication network
in the intermittent operation (DRX) mode.
Fig. 12 is a diagram illustrating an exemplary communication sequence performed between
a communication network and a terminal.
Fig. 13 is a flowchart illustrating a processing procedure performed by the communication
device 50 operating as a terminal corresponding to an occurred event in a communication
network in the intermittent operation (DRX) mode.
Fig. 14 is a flowchart illustrating another exemplary processing procedure performed
by the communication device 50 operating as a terminal corresponding to an occurred
event in a communication network in the intermittent operation (DRX) mode.
Fig. 15 is a diagram illustrating an exemplary communication control procedure between
a MTC user, a MTC server, a communication network and a MTC terminal.
MODE FOR CARRYING OUT THE INVENTION
[0039] An embodiment according to the present invention will be described below in detail
with reference to the drawings.
[0040] A structure of a network to which the present invention is applied will be described
first. In the following description, MTC-related parts will be mainly described but
terminals and servers other than MTC may be present in a communication network.
[0041] Fig. 1 schematically illustrates a structure of a communication network to which
the present invention is applied. In the Figure, the communication network is a third
generation mobile communication system whose specification is defined by 3GPP, for
example. The communication network is configured of at least a base station, and may
be arranged with a mobility management entity (MME) of a terminal and a gateway (GW)
for an external network. The external network described herein is an IP (Internet
Protocol) network, for example.
[0042] The terminals accommodated in the communication network include MTC terminals not
directly used by persons for communication such as meters, automatic vendors and electronic
advertisements. The MTC terminal is a terminal for making communication with a MTC
user via a communication network, a MTC server or the like. The MTC user is a user
utilizing MTC. For example, person-operating client machines or programs taking persons'
works may be considered as part of the MTC users.
[0043] The MTC server is a server present between the MTC user and the MTC terminal, and
is directed for converting an application level request from the MTC user into information
for the MTC terminal or transmitting the information for the MTC terminal to the MTC
terminal via the communication network. The server is not particularly limited in
a physical meaning, and the functions of the MTC server can be provided in various
forms.
[0044] In the exemplary structure of the communication network illustrated in Fig. 1, a
terminal, a base station, a MME and a GW are arranged, respectively, but multiple
ones may be arranged, respectively. In the Figure, the MTC server is present outside
the GW or on an external network. When a MTC user is not an operator of the communication
network, the illustrated structure may be assumed. The MTC user other than the operator
of the communication network assumes an operator who collects information from the
MTC terminal or distributes information to the MTC terminal, for example.
[0045] Fig. 2 schematically illustrates other structure of the communication network to
which the present invention is applied. It is mainly different from the exemplary
structure of the communication network illustrated in Fig. 1 in that the MTC server
is arranged inside the communication network.
[0046] The MTC server is depicted as a physically-independent device in both the exemplary
structures of the communication network illustrated in Fig. 1 and Fig. 2, but the
present invention is not limited thereto, and the GW or other device may support the
functions of the MTC server, for example.
[0047] DRX set in the communication network according to the embodiment of the present invention
will be next described.
[0048] For example, the MTC terminal is relatively lower in a necessary communication frequency
than normal terminals, and needs to reduce consumed power of the terminal by DRX.
For 3GPP, an outline of intermittent reception is described as DRX (described above).
Fig. 3 illustrates an exemplary structure of a radio frame transmitted from the base
station to the terminal, which is defined by LTE of 3GPP. The radio frame is formed
in a three-layer hierarchy of time slot (Slot), subframe (Subframe) and radio frame
(Radio Frame) in ascending order of time unit.
[0049] A time slot with 0.5 milliseconds is configured of seven OFDM symbols #0 to #6 (in
the case of unicast transmission), and is a unit of a demodulation processing when
being received on the user (mobile station) side. A subframe with one millisecond
is configured of two successive time slots, and is a transmission time unit of a correction-encoded
data packet. A radio frame with 10 milliseconds is configured of ten successive subframes
#0 to #9 (that is, 20 time slots), and is a basic unit for multiplexing of all the
physical channels.
[0050] With different subcarriers or different time slots, each terminal accommodated in
the base station may make communication without mutual interference. A minimum unit
of radio resource allocation, which is directed for blocking successive subcarriers
and is called "resource block (RB)", is defined in LTE.
[0051] A scheduler mounted on the base station allocates radio resources in units of resource
block to each user. Fig. 4 schematically illustrates how the resource blocks are allocated.
The resource block is configured of 12 subcarriers x one time slot (7 OFDM symbols
= 0.5 milliseconds), and in the Figure, the bold-line frame corresponds to one resource
block. Up to three OFDM symbols from the head of the subframe are used for a control
channel called "L1/L2 control signaling" (in the illustrated example, only one symbol
from the head is used for the control channel). The scheduler of the base station
can allocate the resource blocks per subframe or at intervals of 1 millisecond. Position
information of the resource block is called scheduling. The scheduling information
on uplink from the terminal to the base station and the scheduling information on
downlink from the base station to the terminal are both described in the downlink
control channel. Each user can recognize the resource blocks allocated to him/her
through the control channel.
[0052] Though omitted in Fig. 3 and Fig. 4, it is noted that channels and signals are present.
[0053] In a radio frame, subframes, slots or symbols storing control information therein
are transmitted from the base station at a predetermined time and frequency. The control
information described herein is paging information describing call information or
scheduling information describing channel allocation, for example. Each terminal accommodated
in the base station receives and acquires the control information thereby to know
network information of the network to which the terminal is connected, or resource
allocation of subframes, slots and frequencies.
[0054] In DRX, the terminal enters the ON state in a predetermined cycle to receive predetermined
subframes, slots or symbols of radio frames among the radio frames transmitted from
the base station, and enters the OFF (sleep) state in other times. At least the receiver
is stopped in the OFF state so that the terminal can achieve a reduction in consumed
power.
[0055] Fig. 5 schematically illustrates an exemplary structure of the communication device
operating as a terminal in the network of the base station.
[0056] The illustrated communication device 50 includes one or more antennas 51, an analog
processing unit 52, a digital transmission processing unit 53, a digital reception
processing unit 54, an application processing unit 55, and a DRX control unit 56.
[0057] The digital transmission processing unit 53 performs digital modulation such as OFDM
on transmission data requested to transmit by the application processing unit 55.
A transmission circuit in the analog processing unit 52 analog-converts a digital
transmission signal, further up-converts it to a radio frequency band and amplifies
its power to be delivered from the antenna 51.
[0058] A reception signal at the antenna 51 is amplified with low noise and down-converted
in a reception circuit in the analog processing unit 52, and then digital-converted.
The digital reception processing unit 54 performs digital demodulation such as OFDM
on a digital reception signal, and recovers and passes reception data to the application
processing unit 55. The digital reception processing unit 54 performs a synchronization
(or pull-in) processing, frequency correction, channel estimation and the like.
[0059] The communication device 50 includes two or more antennas 51 thereby to make spatial
multiplex communication. One or more antennas 51 may be employed and the present invention
is not limited to a specific number of antennas.
[0060] The communication device 50 has a normal operation mode for always operating the
communication processing units such as the analog processing unit 52, the digital
transmission processing unit 53 and the digital reception processing unit 54, and
a power-saving mode for turning off at least part of the circuits in the communication
processing units thereby to reduce consumed power. An exemplary power-saving mode
is an intermittent operation mode for intermittently performing DRX or a communication
operation of the communication processing units, where at least part of the circuits
in the communication processing units is turned off in a period in which the communication
operation stops, thereby achieving low consumed power. The DRX control unit 56 controls
for causing the communication processing units to perform the intermittent communication
operation in the intermittent operation mode while the communication device 50 is
acquiring necessary information from the communication network.
[0061] Generally, the intermittent operation repeatedly switches on and off the communication
operation of the communication processing units with a cycle of DRX. When a rate of
the period in which the communication operation is turned on in the cyclic period,
that is, a duty ratio is low, low consumed power is more effective but a time in which
information can be acquired from the communication network is shorter. The most basic
intermittent operation employs only one DRX cycle, but to the contrary, the network
according to the present embodiment is mainly characterized in that a period for the
intermittent operation is determined in combination of the cycles of DRX with different
lengths in a hierarchy manner. Upper DRX in the hierarchy has a longer cycle than
lower DRX. A period using the cycle of the immediately lower DRX is determined based
on the information on the cycle of the upper DRX. In the period using the information
on the cycle of the lowermost DRX, the intermittent operation of the communication
processing units is controlled based on the information on the cycle of the DRX. In
the present specification, a period using the information on the cycle of the lowermost
DRX is called "intermittent operation period." The communication device 50 in the
intermittent operation mode performs the intermittent operation on the communication
processing units only in the intermittent operation period, and keeps at least part
of the circuits in the communication processing units in the OFF state (the long sleep
state) in the long period other than the intermittent operation period, thereby achieving
low consumed power. The communication device 50 in the intermittent operation mode
activates the communication operation of the communication processing units only in
the intermittent operation period thereby to set the intermittent operation period
for acquiring necessary information from the communication network.
[0062] The number of cycles or modes of DRX used in a hierarchy manner is not particularly
limited. In the following, for simplified description, assuming that two cycles of
DRX with different lengths of the first DRX "DRX1" with a long cycle T_DRX1 and the
second DRX "DRX2" with a short cycle T_DRX2 (where, T_DRX1>T_DRX2) and immediately
lower than the DRX1 are used in a hierarchy manner, the operations of the communication
network will be considered.
[0063] The DRX control unit 56 in Fig. 5 uses the information on the cycle T_DRX1 of the
upper DRX1 to determine a period using the information on the cycle T_DRX2 of the
lower DRX2. Since the DRX2 is the lowermost DRX, the period using the information
on the cycle T_DRX2 corresponds to the intermittent operation period, and in the period,
the information on the cycle T_DRX2 is used to control the intermittent operation
of the communication processing units. Since the communication operation stops in
the long period other than the intermittent operation period in the intermittent operation
mode, at least part of the circuits in the communication processing units is kept
in the OFF state (in the long sleep state), thereby achieving low consumed power.
The communication device 50 in the intermittent operation mode activates the communication
operation of the communication processing units only in the intermittent operation
period, and thus the cycle T_DRX1 of the DRX1 and the cycle T_DRX2 of the DRX2 are
set in the communication network for the proper intermittent operation period in which
necessary information can be acquired from the communication network. In the present
specification, information on DRX in the communication network including the information
on the cycle T_DRX1 of the DRX1 and the information on the cycle T_DRX2 of the DRX2
will be called "DRX control information."
[0064] Fig. 6 illustrates an exemplary internal structure of the DRX control unit 56. The
DRX control unit 56 includes a DRX information setting unit 61, a DRX switch unit
62, a DRX1 determination unit 63, a DRX2 determination unit 64, and a timing count
unit 65.
[0065] The DRX information setting unit 61 sets the DRX switch unit 62, the DRX1 determination
unit 63 and the DRX2 determination unit 64 according to the DRX control information
received from the application processing unit 55. The DRX information setting unit
61 uses a timing count signal from the timing count unit 65 to generate a DRX1 timing
signal with the cycle T_DRX1 of the DRX1 and a DRX2 timing signal with the cycle T_DRX2
of the DRX2 and to supply them to the DRX switch unit 62, the DRX1 determination unit
63 and the DRX2 determination unit 64. The DRX control information includes information
on a duty ratio between the cycle T_DRX1 of the DRX1 and the DRX1 timing signal and
a duty ratio between the cycle T_DRX2 of the DRX2 and the DRX2 timing signal. The
information on the duty ratios described herein may be the values of the duty ratios,
or the values directly indicating the length of the ON period and the length of the
OFF period of the DRX1 timing signal and the DRX2 timing signal.
[0066] The DRX switch unit 62 switches to the period using the DRX2 timing signal or the
intermittent operation period based on the ON/OFF switch timing of the DRX1 timing
signal input from the DRX information setting unit 61, and inputs an instruction into
the DRX1 determination unit 63 and the DRX2 determination unit 64.
[0067] The DRX1 determination unit 63 compares the DRX1 timing signal input from the DRX
information setting unit 61 with the timing count signal input from the timing count
unit 65, and controls the intermittent operation of the digital reception processing
unit 54 and the analog processing unit 52 in the period other than the intermittent
operation period in the intermittent operation mode.
[0068] The DRX2 determination unit 64 compares the DRX2 timing signal input from the DRX
information setting unit 61 with the timing count signal input from the timing count
unit 65, and controls the intermittent operation of the digital transmission processing
unit 53, the digital reception processing unit 54 and the analog processing unit 52
in the intermittent operation period.
[0069] Fig. 7 illustrates exemplary DRX using DRX1 with a long cycle T_DRX1 and DRX2 with
a short cycle T_DRX2 in a hierarchy manner (T_DRX1≥T_DRX2). In the illustrated example,
the intermittent operation period is as long as the ON period of the upper DRX1 timing
signal and the communication operation is performed only in the ON period of the lower
DRX2 timing signal in the intermittent operation period. Thus, the ON period of the
upper DRX1 timing signal is inevitably longer than the ON period of the lower DRX2
timing signal.
[0070] The intermittent operation period in which the communication processing units are
intermittently operated based on the immediately lower DRX2 timing signal is set based
on the upper DRX1 timing signal in the hierarchy DRX.
[0071] In the example illustrated in Fig. 7, when entering the ON period of the DRX1 timing
signal, the DRX switch unit 62 determines to start the intermittent operation period,
and entering the OFF period of the DRX1 timing signal, determines to terminate the
intermittent operation period. The DRX1 determination unit 63 keeps at least part
of the circuits in the digital transmission processing unit 53, the digital reception
processing unit 54 and the analog processing unit 52 in the OFF state in other than
the intermittent operation period (that is, puts the terminal in the long sleep state).
[0072] When entering the intermittent operation period, the DRX2 determination unit 64 determines
ON/OFF of the DRX2 timing signal, and turns on the digital transmission processing
unit 53, the digital reception processing unit 54 and the analog processing unit 52
in the ON period of the DRX2 timing signal, and waits for the control information
to be received from the radio frames or the communication network (the base station).
The DRX2 determination unit 64 turns off the digital transmission processing unit
53, the digital reception processing unit 54 and the analog processing unit 52 in
the OFF period of the DRX2 timing signal (that is, puts the terminal in the short
sleep state).
[0073] The cycles of DRX with different lengths are used in a hierarchy manner as illustrated
in Fig. 7 so that the terminal can acquire necessary information from the communication
network in the short DRX cycle while achieving a reduction in consumed power of the
terminal in the long DRX cycle. The number of cycles of the hierarchy DRX is not limited
to two. The DRX unit is a subframe, but reception is possible in other unit.
[0074] Fig. 8 illustrates other exemplary DRX using DRX1 with a long cycle T_DRX1 and DRX2
with a short cycle T_DRX2 in a hierarchy manner. T_DRX1>T_DRX2 is assumed. In the
illustrated example, a rise of the upper DRX1 timing signal is used to determine the
start point and the end point of the intermittent operation period, and thus the length
of the ON period is meaningless. Since the communication operation is performed only
in the ON period of the lower DRX2 timing signal in the intermittent operation period,
when a duty ratio is made higher, the reception chances increase but lower consumed
power is less effective.
[0075] The intermittent operation period for intermittently operating the communication
processing units based on the immediately lower DRX2 timing signal is set based on
the upper DRX1 timing signal in the hierarchy DRX. While the intermittent operation
period is in the ON period of the DRX1 timing signal in the example illustrated in
Fig. 7, the intermittent operation period starts when the DRX1 timing signal is turned
on outside the intermittent operation period and the intermittent operation period
ends when the DRX1 timing signal is turned on in the intermittent operation period
in the example illustrated in Fig. 8 (that is, whenever the DRX1 timing signal is
turned on, the intermittent operation period alternately starts and ends in a repeated
manner).
[0076] In the example illustrated in Fig. 8, the DRX switch unit 62 determines to start
the intermittent operation period when the DRX1 timing signal is turned on not in
the DRX2 mode. The DRX switch unit 62 determines to terminate the intermittent operation
period when the DRX1 timing signal is turned on in the intermittent operation period.
[0077] The DRX2 determination unit 64 determines ON/OFF of the DRX2 timing signal in the
intermittent operation period, and turns on the digital transmission processing unit
53, the digital reception processing unit 54 and the analog processing unit 52 and
waits for the control information to be received from the communication network (the
base station) in the ON period of the DRX2 timing signal. The DRX2 determination unit
64 turns off the digital transmission processing unit 53, the digital reception processing
unit 54 and the analog processing unit 52 in the OFF period of the DRX2 timing signal
(that is, puts the terminal in the short sleep state). The DRX1 determination unit
63 turns off the digital transmission processing unit 53, the digital reception processing
unit 54 and the analog processing unit 52 in the period other than the intermittent
operation period (that is, puts the terminal in the long sleep state).
[0078] The cycles of DRX with different lengths are used in a hierarchy manner as illustrated
in Fig. 8 so that the terminal can acquire necessary information from the communication
network in the short DRX cycle while achieving a reduction in consumed power of the
terminal in the long DRX cycle. The number of cycles of the hierarchy DRX is not limited
to two. The DRX unit is a subframe, but reception is possible in other unit.
[0079] Fig. 9 illustrates still another exemplary DRX using the DRX1 mode with a long cycle
T_DRX1 and the DRX2 mode with a short cycle T_DRX2 in a hierarchy manner. T_DRX1>T_DRX2
is assumed. In the illustrated example, it may be desirable that the ON period of
the upper DRX1 timing signal is longer than the ON period of the lower DRX2 timing
signal (ditto). Since the intermittent operation period is as long as the ON period
of the upper DRX1 timing signal, when the duty ratio is made higher, the reception
chances increase. Since a rise of the lower DRX2 timing signal is used to determine
the start point and the end point of the communication operation in the intermittent
operation period, the length of the ON period is meaningless.
[0080] The intermittent operation period for intermittently operating the communication
processing units based on the immediately lower DRX2 timing signal is set based on
the upper DRX1 timing in the hierarchy DRX. In the example illustrated in Fig. 9,
the intermittent operation period is in the ON period of the DRX1 timing signal similarly
as in the example illustrated in Fig. 7. While the communication operation is performed
in the ON period of the DRX2 timing signal in the intermittent operation period in
the example illustrated in Fig. 7, the communication operation starts when the DRX2
timing signal is turned on while the communication operation is stopping in the intermittent
operation period, and the communication operation stops when the DRX2 timing signal
is turned on during the communication operation (that is, whenever the DRX2 timing
signal is turned on, the communication operation alternately starts and stops in a
repeated manner) in the example illustrated in Fig. 9.
[0081] In the example illustrated in Fig. 9, the DRX switch unit 62 determines to start
the intermittent operation period when entering the ON period of the DRX1 timing signal,
and determines to terminate the intermittent operation period when entering the OFF
period of the DRX1 timing signal. The DRX1 determination unit 63 keeps at least part
of the circuits in the digital transmission processing unit 53, the digital reception
processing unit 54 and the analog processing unit 52 in the OFF state in other than
the intermittent operation period (that is, puts the terminal in the long sleep state).
[0082] In the intermittent operation period, the DRX2 determination unit 64 starts the communication
operation when the DRX2 timing signal is turned on while the communication processing
units such as the digital transmission processing unit 53, the digital reception processing
unit 54 and the analog processing unit 52 stop the communication operation, and waits
for the control information to be received from the radio frames or the communication
network (the base station). When the DRX2 timing signal is turned on during the communication
operation of the communication processing units, the communication operation of the
communication processing units stops (that is, the terminal is put in the sleep state).
Thereafter, whenever the DRX2 timing signal is turned on, the reception waiting state
and the (short) sleep state are alternately switched.
[0083] The cycles of DRX with different lengths are used in a hierarchy manner as illustrated
in Fig. 9, the terminal can acquire necessary information from the communication network
in the short DRX cycle while achieving a reduction in consumed power of the terminal
in the long DRX cycle. The number of cycles of the hierarchy DRX is not limited to
two. The DRX unit is a subframe, but reception is possible in other unit.
[0084] In the examples illustrated in Fig. 7 to Fig. 9, the radio frame are continuously
received only in the intermittent operation period in the intermittent operation mode.
However, when the terminal can finish all the required reception processing in the
intermittent operation period, the communication processing units may exit the intermittent
operation period and may be turned off without waiting for the intermittent operation
period determined based on the DRX1 timing signal to end. Thereby, the terminal can
further achieve a reduction in consumed power.
[0085] When the cycles of DRX with different lengths are used in a hierarchy manner as described
above, it is assumed that the MTC terminal in the intermittent operation mode is in
the OFF (sleep) state for a long time other than the intermittent operation period.
Thus, when the MTC terminal transits to the ON state and receives the radio frames
again, correction (synchronization or pull-in) of the receiver may be required. A
method using a known part of a signal transmitted from the base station, or the like
is specifically assumed in order to correct the receiver, but the present invention
is not limited to a specific correction method.
[0086] For a timing when the MTC terminal corrects the receiver, it is assumed that pull-in
or synchronization is performed when the receiver is not in ON after the intermittent
operation period starts. Thereby, it is possible to correct the receiver in order
to keep the reception quality while achieving a reduction in consumed power when the
communication processing units are in the OFF (sleep) state in the period other than
the intermittent operation period determined by the DRX1 timing signal. The receiver
may be corrected in other timing. For example, also in the OFF state other than the
intermittent operation period, the terminal may voluntarily make a correction. In
this case, the terminal temporarily enters the ON state.
[0087] Fig. 10 illustrates the processing procedure performed by the communication device
50 operating as a terminal in the communication network in the intermittent operation
(DRX) mode in a form of flowchart. Herein, when entering the intermittent operation
mode, the terminal uses the long cycle T_DRX1 and the short cycle T_DRX2 in a hierarchy
manner.
[0088] When the intermittent operation mode starts according to the determination by the
DRX switch unit 62 (step S1001), the digital reception processing unit 54 performs
a correction processing such as synchronization or pull-in before the communication
processing units are turned on (step S1002).
[0089] Thereafter, the DRX switch unit 62 monitors the DRX1 timing signal and waits for
a timing of entering the intermittent operation period to arrive (No in step S1003).
Then, when the timing of entering the intermittent operation period arrives (Yes in
step S1003), the terminal enters the intermittent operation period (step S1004).
[0090] In the intermittent operation period, the DRX2 determination unit 64 compares the
DRX2 timing signal input from the DRX information setting unit 61 with the timing
count signal input from the timing count unit 65, and waits for a period for performing
the reception operation to arrive (No in step S1005).
[0091] Then, when the period for performing the reception operation arrives (Yes in step
S1005), the DRX2 determination unit 64 turns on the receiver, that is, the digital
reception processing unit 54 and the analog processing unit 52, and receives predetermined
control information from the communication network (step S1006).
[0092] The control information described herein is paging information describing call information
or scheduling information describing channel allocation, for example. The control
information received from the communication network is analyzed to check whether a
channel is allocated to the terminal (step S1007). When a channel is allocated (Yes
in step S1007), the digital reception processing unit 54 and the analog processing
unit 52 receive the allocated channel (step S1008), and performs processing according
to the contents received in the application processing unit 55 (step S1009).
[0093] Thereafter, the DRX switch unit 62 checks whether to continue the intermittent operation
period based on the DRX1 timing signal (step S1010). When the DRX2 mode is to be continued
(Yes in step S1010), the processing returns to step S1005 to wait for the period for
performing the reception operation to arrive. When the intermittent operation period
is not to be continued (No in step S1010), the processing returns to step S1001.
[0094] Fig. 11 illustrates another exemplary processing procedure performed by the communication
device 50 operating as a terminal in the communication network in the intermittent
operation (DRX) mode in a form of flowchart. Herein, when entering the intermittent
operation mode, the terminal uses the long cycle T_DRX1 and the short cycle T_DRX2
in a hierarchy manner (ditto).
[0095] When the intermittent operation mode starts according to the determination by the
DRX switch unit 62 (step S1101), the DRX switch unit 62 monitors the DRX1 timing signal,
and waits for a timing of entering the intermittent operation period to arrive (No
in step S1102). Then, when the timing of entering the intermittent operation period
arrives (Yes in step S1102), the terminal enters the intermittent operation period
(step S1103).
[0096] When entering the intermittent operation period, the receiver or the digital reception
processing unit 54 performs the correction processing such as synchronization or pull-in
before the receiver is turned on (step S1104).
[0097] In the intermittent operation period, the DRX2 determination unit 64 compares the
DRX2 timing signal input from the DRX information setting unit 61 with the timing
count signal input from the timing count unit 65, and waits for a period for performing
the reception operation to arrive (No in step S1105).
[0098] When the period for performing the reception operation arrives (Yes in step S1105),
the DRX2 determination unit 64 turns on the receiver, that is, the digital reception
processing unit 54 and the analog processing unit 52, and receives predetermined control
information from the communication network (step S1106).
[0099] Then, the control information received from the communication network is analyzed
and a check is made as to whether a channel is allocated to the terminal (step S1107).
Then, when a channel is allocated (Yes in step S1107), the digital reception processing
unit 54 and the analog processing unit 52 receive the allocated channel (step S1108),
and perform processing according to the contents received in the application processing
unit 55 (step S1109).
[0100] Thereafter, the DRX switch unit 62 checks whether to continue the intermittent operation
period based on the DRX1 timing signal (step S1110). When the intermittent operation
period is to be continued (Yes in step S1110), the processing returns to step S1105
to wait for the period for performing the reception operation to arrive. When the
intermittent operation period is not to be continued (No in step S1110), the processing
returns to step S1001.
[0101] Fig. 12 illustrates an exemplary communication sequence performed between the communication
network and the MTC terminal.
[0102] In the communication network, for example, the base station generates DRX control
information necessary for performing DRX at the terminal (SEQ1201). Herein, the DRX
control information is generated for using a plurality of DRX modes with different
cycles in a hierarchy manner. The DRX control information includes the information
on the cycle T_DRX1 of the DRX1 and the information on the cycle T_DRX2 of the DRX2.
Then, the generated DRX control information is notified to the MTC terminal from the
communication network (SEQ1202).
[0103] Then, the MTC terminal sets the cycles and the duty ratios of the DRX1 timing signal
and the DRX2 timing signal based on the received DRX control information, and performs
DRX according to any operation procedure illustrated in Fig. 7 to Fig. 9, for example
(SEQ1203).
[0104] The communication network generates system information, paging information, scheduling
information and the like (SEQ1204). Then, after the cycles and the duty ratios of
the DRX1 timing signal and the DRX2 timing signal are set for the MTC terminal as
described above, the system information, the paging information, the scheduling information
and the like are transmitted to the MTC terminal so as to conform to the cycles (or
the subframes in which the MTC terminal performs the reception operation) (SEQ1205).
[0105] When receiving the system information, the paging information, the scheduling information
and the like, the MTC terminal performs processing according to the information (SEQ1206).
Thereby, the MTC terminal can both reduce consumed power with the long cycle T_DRX1
(the long sleep state) and acquire necessary information from the communication network.
[0106] In the exemplary communication sequence illustrated in Fig. 12, it is assumed that
DRX in the MTC terminal is basically set from the communication network side. Typically,
DRX is set from the communication network side according to a communication frequency
of the network information.
[0107] However, it is assumed that the MTC terminal is in the sleep state for a long time,
but communication may be needed due to an occurrence of an event at a timing other
than the initial schedule. The event described herein may include an emergency situation
or failure occurring in the MTC terminal. In consideration of convenience of the MTC,
even when such an event occurs, the communication network and the MTC terminal need
to properly operate. In the following, the DRX control system depending on an occurred
event will be considered.
[0108] There has been employed, as an example in which the cycles of DRX with different
lengths are used in a hierarchy manner, the case in which two DRX modes of the first
DRX "DRX,1" with a long cycle T_DRX1 and the second DRX "DRX2" with a short cycle
T_DRX2 (where T_DRX1>T_DRX2) and immediately lower than the DRX1 are used in a hierarchy
manner. To the contrary, two cycles with different lengths of TDRX1a and T_DRX1b are
defined as the cycles corresponding to the DRX1 (where T_DRX1a>T_DRX1b) in case the
communication is needed due to an occurred event. The DRX1 timing signal driven at
the cycle T_DRX1a is typically used to determine the intermittent operation period,
but when an event occurs, the cycle is switched to the DRX1 timing signal driven at
T_DRX1b to determine the intermittent operation period. Specifically, the DRX information
setting unit 61 may change the DRX1 cycle from T_DRX1a to T_DRX1b to change the DRX1
timing signal, and the DRX switch unit 62 may determine the intermittent operation
period by use of the changed DRX1 timing signal. With the cycle switching, the terminal
can rapidly make connection to the communication network when an event occurs.
[0109] Fig. 13 illustrates a processing procedure performed by the communication device
50 operating as a terminal corresponding to an occurred event in the communication
network in the intermittent operation (DRX) mode in a form of flowchart.
[0110] When the intermittent operation mode starts according to the determination by the
DRX switch unit 62 (step S1301), the DRX information setting unit 61 first sets the
cycle of the DRX1 at T_DRX1a and then generates the DRX1 timing signal.
[0111] Then, a check is made as to whether a predetermined event has occurred in the intermittent
operation mode (in the period not in the intermittent operation period) (step S1302).
[0112] For an event, an occurrence of an even at the application layer level in the MTC
terminal or sensor detection is assumed. The present invention is not limited to a
specific event detection method.
[0113] When a predetermined event has occurred (Yes in step S1302), the DRX information
setting unit 61 switches the cycle of the DRX1 from T_DRX1a to T_DRX1b thereby to
change the DRX1 timing signal (step S1303). Consequently, the DRX switch unit 62 uses
the changed DRX1 timing signal to determine the intermittent operation period.
[0114] On the other hand, when a predetermined event has not occurred (No in step S1302),
the DRX information setting unit 61 generates the DRX1 timing signal with the cycle
of the DRX1 kept at T_DRX1a, and the DRX switch unit 62 uses the DRX1 timing signal
to determine the intermittent operation period.
[0115] The DRX switch unit 62 monitors the DRX1 timing signal and waits for a timing of
entering the intermittent operation period to arrive (No in step S1304). Then, when
the timing of entering the intermittent operation period arrives (Yes in step S1304),
the terminal enters the intermittent operation period (step S1305).
[0116] When entering the intermittent operation period, the receiver or the digital reception
processing unit 54 performs the correction processing such as synchronization or pull-in
prior to activating the reception operation (step S1306).
[0117] In the intermittent operation period, the DRX2 determination unit 64 compares the
DRX2 timing signal input from the DRX information setting unit 61 with the timing
count signal input from the timing count unit 65, and waits for a period for performing
the reception operation to arrive (No in step S1307).
[0118] Then, when the period for performing the reception operation arrives (Yes in step
S1307), the DRX2 determination unit 64 turns on the receiver, that is, the digital
reception processing unit 54 and the analog processing unit 52, and receives predetermined
control information from the communication network (step S1308).
[0119] Then, the control information received from the communication network is analyzed
and a check is made as to whether a channel is allocated to the terminal (step S1309).
Then, when a channel is allocated (Yes in step S1309), the digital reception processing
unit 54 and the analog processing unit 52 receive the allocated channel (step S1310),
and performs processing according to the contents received in the application processing
unit 55 (step S1311).
[0120] Thereafter, the DRX switch unit 62 checks whether to continue the intermittent operation
period based on the DRX1 timing signal (step S1312). When the intermittent operation
period is to be continued (Yes in step S1312), the processing returns to step S1307
to wait for a period for performing the reception operation to arrive. When the intermittent
operation is not to be continued (No in step S1312), the processing returns to step
S1301.
[0121] Fig. 14 illustrates another exemplary processing procedure performed by the communication
device 50 operating as a terminal corresponding to an occurred event in the communication
network in the intermittent operation (DRX) mode in a form of flowchart.
[0122] When the intermittent operation mode starts according to the determination by the
DRX switch unit 62 (step S1401), the DRX information setting unit 61 sets the cycle
of the DRX1 at T_DRX1a and generates the DRX1 timing signal.
[0123] Then, a check is made as to whether a predetermined event has occurred in the intermittent
operation mode (in the period not in the intermittent operation period) (step S1402).
[0124] Herein, when a predetermined event has occurred (Yes in step S1402), the terminal
exits the intermittent operation mode and enters the normal communication state to
always perform the reception operation (step S1403). Then, the terminal issues a request
of connecting to the communication network (the base station) (step S1404), and when
connection is established, performs the communication processing according to the
predetermined contents (step S1405). Thereafter, the terminal returns to step S1401.
[0125] On the other hand, when a predetermined event has not occurred (No in step S1402),
the DRX switch unit 62 monitors the DRX1 timing signal and waits for a timing of entering
the intermittent operation period to arrive (No in step S1406). Then, when the timing
of entering the intermittent operation period arrives (Yes in step S1406), the terminal
enters the intermittent operation period (step S1407).
[0126] When entering the intermittent operation period, the receiver or the digital reception
processing unit 54 performs the correction processing such as synchronization or pull-in
before the receiver is turned on (step S1408).
[0127] In the intermittent operation period, the DRX2 determination unit 64 compares the
DRX2 timing signal input from the DRX information setting unit 61 with the timing
count signal input from the timing count unit 65, and waits for a period for performing
the reception operation to arrive (No in step S1409).
[0128] When the period for performing the reception operation arrives (Yes in step S1409),
the DRX2 determination unit 64 turns on the receiver, that is, the digital reception
processing unit 54 and the analog processing unit 52, and receives predetermined control
information from the communication network (step S1410).
[0129] Then, the control information received from the communication network is analyzed,
and a check is made as to whether a channel is allocated to the terminal (step S1411).
Then, when a channel is allocated (Yes in step S1411), the digital reception processing
unit 54 and the analog processing unit 52 receive the allocated channel (step S1412)
and perform processing according to the contents received in the application processing
unit 55 (step S1413).
[0130] Thereafter, the DRX switch unit 62 checks whether to continue the intermittent operation
period based on the DRX1 timing signal (step S1414). When the intermittent operation
period is to be continued (Yes in step S1414), the processing returns to step S1409
to wait for a period for performing the reception operation to arrive. When the intermittent
operation period is not to be continued (No in step S1414), the processing returns
to step S1401.
[0131] MTC applications may include meters, automatic vendors, electronic advertisements
and the like. Thus, an intention of the MTC user is desirably reflected on the communication
contents and the communication schedule of the MTC terminal. Particularly, the communication
schedule largely has a relationship with DRX. In consideration of the MTC applications,
it is naturally expected that the communication schedule is longer, such as daily,
weekly and monthly, unlike the typical communication.
[0132] The communication schedule desired by the MTC user needs to be put under the DRX
control on the communication network side in order to efficiently apply the DRX control
to the system. Therefore, it is desirable that a function of notifying the communication
schedule desired by the MTC user to the communication network is inside the communication
network or outside the communication network. A MTC server is assumed for realizing
the function.
[0133] Fig. 15 illustrates an exemplary communication control procedure between the MTC
user, the MTC server, the communication network and the MTC terminal. In the Figure,
the MTC user, the MTC server, the communication network and the MTC terminal are classified
not physically but logically. For example, the MTC server can also have the functions
of the MTC user or the GW in the communication network can also have the functions
of the MTC server. In Fig. 15, only exchange of information at the logic level and
in the application layer is noted, and ACK/NACK or retransmission when a communication
error occurs in the lower layer is omitted. Any protocol is applicable to the protocol
in the lower layer.
[0134] The functions of the MTC server for controlling DRX with respect to the communication
network may have the following.
[0135]
- (1) A function of receiving information on the contents of the MTC or the schedule
from the MTC user.
- (2) A function of notifying the communication interval and the cycle of the target
MTC terminal to the communication network based on the schedule.
[0136] For the function (1), the information input from the MTC user may be manually input
by the MTC user or may be automatically generated by the MTC user (the client machine).
The input method is not limited.
[0137] For the function (2), the MTC server may simply notify the schedule information as
time information to the communication network or may convert and notify it into a
unit (radio frame, subframe, slot or the like) according to the frame structure of
the communication network to the communication network.
[0138] When receiving the schedule information from the MTC server, the communication network
generates control information on the actual DRX from the schedule, and controls DRX
of the target MTC terminal. The DRX control information is notified to the MTC terminal
via the base station. The schedule information received from the MTC server can be
longer (time, day, week, month or the like) as time information handled by the communication
network. Thus, it is desirable to consider a hierarchy of DRX at the communication
network level such that the MTC terminal can both reduce consumed power and acquire
the network information. The longest DRX cycle needs to be shorter than the schedule
cycle set by the MTC user in the DRX setting at the communication network level.
INDUSTRIAL APPLICABILITY
[0139] The present invention has been described above in detail with reference to the specific
embodiment. However, it is apparent that those skilled in the art can modify or replace
the embodiment without departing from the spirit of the present invention.
[0140] The embodiment in which the present invention is applied to the communication network
based on the data communication specification defined by LTE of 3GPP has been mainly
described in the present specification, but the present invention is not limited thereto.
The present invention is applicable to various types of communication networks configured
of the base stations accommodating terminals.
[0141] The embodiment in which the present invention is applied to the MTC terminal not
directly used by persons for communication has been mainly described in the present
specification, but the present invention is not limited thereto. The present invention
is applicable to various types of terminals directly used by persons for communication
other than MTC, or various types of communication systems other than illustrated ones
in Fig. 1 and Fig. 2.
[0142] That is, the present invention is disclosed by way of example, and the described
contents in the present specification should not be definitely interpreted. The range
of claims should be considered for determining the spirit of the present invention.
REFERENCE SIGNS LIST
[0143]
50 |
Communication device |
51 |
Antenna |
52 |
Analog processing unit |
53 |
Digital transmission processing unit |
54 |
Digital reception processing unit |
55 |
Application processing unit |
56 |
DRX control unit |
61 |
DRX information setting unit |
62 |
DRX switch unit |
63 |
DRX1 determination unit |
64 |
DRX2 determination unit |
65 |
Timing count unit |
1. A communication device comprising:
a communication processing unit for performing digital processing and analog processing
for transmitting and receiving data; and
an intermittent operation control unit for determining whether to enter an intermittent
operation period for intermittently operating the communication processing unit per
second cycle by use of information on a first cycle longer than the second cycle,
and for intermittently operating the communication processing unit.
2. The communication device according to claim 1, wherein the communication device has
a normal operation mode in which a communication operation is always performed in
the communication processing unit and an intermittent operation mode in which a communication
operation of the communication processing unit is intermittently performed, and
the intermittent operation control unit determines, based on the first cycle, whether
to enter the intermittent operation period in the intermittent operation mode.
3. The communication device according to claim 1 or 2, wherein the intermittent operation
control unit turns off at least part of circuits in the communication processing unit
in a period other than the intermittent operation period.
4. The communication device according to claim 1, wherein the intermittent operation
control unit generates a first timing signal which is switched on or off by the first
cycle and a second timing signal which is switched on or off by the second cycle based
on control information on the first and second cycles from a predetermined base station
when being accommodated in a communication network of the base station, and
determines the intermittent operation period based on the first timing signal and
intermittently operates the communication processing unit based on the second timing
signal in the intermittent operation period.
5. The communication device according to claim 4, wherein the ON period of the first
timing signal is longer than the ON period of the second timing signal.
6. The communication device according to claim 4, wherein the intermittent operation
control unit assumes the ON period of the first timing signal as the intermittent
operation period, turns off at least part of the circuits in the communication processing
unit in the OFF period of the first timing signal, turns on a communication operation
of the communication processing unit in the ON period of the second timing signal
in the intermittent operation period, and turns off the communication processing unit
in the OFF period of the second timing signal.
7. The communication device according to claim 4,
wherein the intermittent operation control unit starts the intermittent operation
period when the first timing signal is turned on in other than the intermittent operation
period, terminates the intermittent operation period when the first timing signal
is turned on in the intermittent operation period, turns on a communication operation
of the communication processing unit in the ON period of the second timing signal
in the intermittent operation period, and turns off at least part of the circuits
in the communication processing unit in the OFF period of the second timing signal.
8. The communication device according to claim 4, wherein the intermittent operation
control unit assumes the ON period of the first timing signal as the intermittent
operation period, turns off at least part of the circuits in the communication processing
unit in the OFF period of the first timing signal, turns on a communication operation
of the communication processing unit when the second timing signal is turned on in
the OFF state of the communication processing unit in the intermittent operation period,
and turns off the communication processing unit when the second timing signal is turned
on in the ON state of the communication operation of the communication processing
unit.
9. The communication device according to claim 4, wherein the intermittent operation
control unit turns off at least part of the circuits in the communication processing
unit when all necessary reception processing from the communication network ends even
in a period which is determined to turn on the communication processing unit based
on the second timing signal in the intermittent operation period.
10. The communication device according to claim 1, wherein predetermined correction processing
is performed on a receiver in the communication processing unit when at least part
of the circuits in the communication processing unit enters the intermittent operation
period from the OFF state and receives radio frames again.
11. The communication device according to claim 10, wherein predetermined correction processing
is performed on a receiver in the communication processing unit in the intermittent
operation period and when the communication processing unit is in the OFF state.
12. The communication device according to claim 1, further comprising a first-2 cycle
shorter than the first cycle,
wherein the intermittent operation mode control unit uses the first-2 cycle instead
of the first cycle when a predetermined event occurs, and determines whether to enter
the intermittent operation period.
13. A communication method comprising:
a first step of determining whether to enter an intermittent operation period for
intermittently operating a communication device based on information on a first cycle;
and
a second step of switching an ON state of a communication operation of the communication
device and an OFF state of at least part of circuits per second cycle shorter than
the first cycle in the intermittent operation period.
14. The communication method according to claim 13, wherein the communication device has
a normal operation mode of always performing a communication operation and an intermittent
operation mode of intermittently performing a communication operation, and
the first step determines whether to enter the intermittent operation period in the
intermittent operation mode based on the information on the first cycle, and
further has a step of turning off the communication device in other than the intermittent
operation period in the intermittent operation mode.
15. A communication method comprising:
a first step of notifying a communication device in a network of parameters of a first
cycle and parameters of a second cycle shorter than the first cycle; and
a second step of notifying the communication device of control information on the
network in association with a period determined based on the first cycle or the second
cycle.
16. The communication method according to claim 15, wherein the second step notifies the
communication device in the network of the control information on the network in association
with a period in which a communication operation is turned on based on the second
cycle in an intermittent operation period determined by the communication device based
on the first cycle.
17. A communication system comprising:
a base station for operating a communication network; and
a terminal which comprises a communication processing unit for performing digital
processing and analog processing for transmitting and receiving data to and from the
base station, sets a first cycle and a second cycle based on parameters of the first
cycle and parameters of the second cycle shorter than the first cycle, notified from
the communication network, determines a period of entering the second intermittent
operation mode based on the first cycle, determines whether to enter an intermittent
operation period for intermittently operating the communication processing unit per
second cycle by use of the first cycle, and intermittently operates the communication
processing unit.